Keeping healthy

Diet and exercise

GCSE Science A (B1.1.1)

A combination of a balanced diet and regular exercise is needed to help keep the body healthy. Our bodies provide an excellent environment for many microbes which can make us ill once they are inside us. Our bodies need to stop most microbes getting in and deal with any microbes which do get in. Vaccination can be used to prevent infection.

Candidates should use their skills, knowledgeand understanding to:

■ evaluate information about the effect of food on health■ evaluate information about the effect of lifestyle on development of disease■ analyse and evaluate claims made by slimming programmes, and slimming products.

B1.1.1 Diet and exercisea) A healthy diet contains the right balance of the different foods you need and the right amount of energy. Carbohydrates, fats and proteins are used by the body to release energy and to build cells.

Mineral ions and vitamins are needed in small amounts for healthy functioning of the body.

A person is malnourished if their diet is not balanced. This may lead to a person being overweight or underweight. An unbalanced diet may also lead to deficiency diseases or conditions such as Type 2 diabetes.

b) A person loses mass when the energy content of the food taken in is less than the amount of energy expended by the body. Exercise increases the amount of energy expended by the body.

c) The rate at which all the chemical reactions in the cells of the body are carried out (the metabolic rate) varies with the amount of activity you do and the proportion of muscle to fat in your body. Metabolic rate may be affected by inherited factors.

d) Inherited factors also affect our health; for example cholesterol level.

e) People who exercise regularly are usually healthier than people who take little exercise.

Type of food Energy (kJ/ 100g)

Nutrient per 100 g

Carbohydrate Fats Protein Fibre

           

           

           

           

           

           

  Needed for: Found in:

Vitamins and minerals

   

Fruits, vegetables, eggs, milk, meat

Carbohydrates    

 

Protein cell growth and repair  

 

Fibre    

 

Fats and oils   

   

Jan 2011

Jan 2011

Scientists estimate that about one third of cancers in the UK may be linked to obesity.Name two other diseases linked to obesity.

The graph shows the changes in the cancer rate and the changes in the percentage of obese adults in the UK from 1995 to 2006.

Jan 2011

Does the data in the graph prove that obesity causes cancer?

Explain the reason for your answer.

Exercise helps a person to lose weight.Explain why.

Jan 2011

Diet and exercise affect health.4 (a) Many people are obese (very overweight).Obesity can lead to heart disease.Other than heart disease, name two conditions which are linked to obesity.

(2 marks)

June 2010

A European Union report estimates that by 2011, one million children in the Union will be obese and have raised blood cholesterol levels.(a) Body mass is dependent on the metabolic rate of the body.

What is meant by metabolic rate?

(2 marks)

(b) Cholesterol is carried around the body by the two types of lipoprotein: low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs).Describe the relationship between the two types of lipoproteins and heart health. (3 marks)

Jan 2010

The graph shows the number of deaths from heart disease each year in the UK.

The pattern for deaths from heart disease in men is different from the pattern in women.Give two differences between the patterns for men and women.

Suggest two reasons for the difference in the number of deaths from heart disease in men and women between the ages of 40 and 60.

June 2010